Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J123/00—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers
  • C09J123/02—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers not modified by chemical after-treatment
  • C09J123/18—Homopolymers or copolymers of hydrocarbons having four or more carbon atoms
  • C09J123/20—Homopolymers or copolymers of hydrocarbons having four or more carbon atoms having four to nine carbon atoms
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2666/00—Composition of polymers characterized by a further compound in the blend, being organic macromolecular compounds, natural resins, waxes or and bituminous materials, non-macromolecular organic substances, inorganic substances or characterized by their function in the composition
  • C08L2666/02—Organic macromolecular compounds, natural resins, waxes or and bituminous materials
  • C08L2666/24—Graft or block copolymers according to groups C08L51/00, C08L53/00 or C08L55/02; Derivatives thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L53/00—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L53/00—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
  • C08L53/02—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers of vinyl-aromatic monomers and conjugated dienes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L57/00—Compositions of unspecified polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L93/00—Compositions of natural resins; Compositions of derivatives thereof

Definitions

• This invention relates a hot melt adhesive composition.
• this invention relates to hot melt adhesive compositions capable of adhering to smooth substrates such as plastic-based or plastic-finished constructions, particularly high density polyethylene films.
• Hot melt adhesives have found extensive use in industry in bonding, joining or fabrication of various structures, including construction of structures from synthetic polymeric films, such as polyethylene, polypropylene, etc.; foil, including metal foil such as aluminum foil, wax-coated or wax-impregnated cellulosic structures; and various non-woven materials whose constituents are based on polyolefins, polyesters, polyamides and acrylic-type polymers.
• plastic-based or plastic-finished constructions such as polyethylene or polypropylene based extrusion coated, spray coated, or laminated composite constructions.
• plastic-based or plastic-finished constructions such as polyethylene or polypropylene based extrusion coated, spray coated, or laminated composite constructions.
• the change in various packaging and disposable laminate from fibrous substrates, such as fabrics and paper or paperboard, to plastics based on synthetic polymers also necessitates that the various adhesives chosen to hold the structures together be compatible with the materials of construction, since the altered surface chemistry of such materials may not be adhesion compatible with traditionally-available hot melt adhesives.
• Hot melt adhesives based on homopolymers or copolymers of 1-butene are commonly used to bond fabrics or non-woven sheets to other porous or semi-porous substrates.
• Poly-1-butenes' polymorphic nature and unique crystallization half-life allow adhesives based on this polymer to flow and remain tacky long after they have cooled to room temperature and thus have relatively long open time.
• adhesion open time is the maximum time at which adhesion (adhesion to itself or to a substrate) can take place for material after it is cooled from the melt to room temperature. Consequently, poly-1-butene based hot melt adhesives can be easily applied to cold substrates and will cold flow into porous substrates before the material undergoes further transition and densification.
• Disposable articles such as baby diapers, adult incontinence briefs, sanitary napkins, etc. typically use adhesives between the outer spun-bonded non-woven fabric, often made of polyolefins such as polypropylene, and the adsorbent core. Adhesives are also used between the absorbent core and the polyolefin liquid barrier, typically a polyolefin film such as a polyethylene film. These adhesives typically have hot melt (177°C) viscosities of less than 10,000 cP and therefore can be applied by spray coating techniques.
• Poly-1-butene adhesives have offered formulators unique opportunities in the market as the adhesive between the polypropylene fabric and the absorbent core.
• poly-1-butene inherently does not adhere very well to smooth surfaces, which have less surface areas than fabrics, such as painted/coated metals and polyolefin films, especially those outer liquid barrier films made of polyolefins such as polyethylenes. Because of this, formulators and diaper manufacturers were not able to utilize poly-1-butene based adhesives to adhere outer liquid barrier films until Lakshmanan et al. (U.S. Patent No. 4,833,192) added liquid polybutenes, copolymers of isobutylene and butenes, to poly-1-butene adhesives to enhance their adhesion to polyethylene film.
• the present invention provides poly-1-butene based hot melt adhesives with good adhesion to both polyolefin fabrics and smooth polyolefin films which are superior to those containing liquid polybutenes.
• a hot melt adhesive composition comprising a poly-1-butene polymer, a tackifier resin, and from 3 to 25 wt.% of a liquid or semi-liquid, hydrogenated or partially hydrogenated, conjugated diene polymer prepared by anionic polymerization that has a molecular weight of at most about 40.000.
• the present invention is directed to a composition suitable for making a hot melt adhesive composition
• a composition suitable for making a hot melt adhesive composition comprising (i) from 20 to 60 wt.%, specifically from 30 to 55 wt.%, more specifically from 34 to 43 wt.% of poly-1-butene polymer; (ii) from 3 to 25 wt.%, specifically from 5 to 20 wt.%, more specifically from 7 to 16 wt.% of the liquid or semi-liquid, low molecular weight and/or low viscosity hydrogenated polydiene polymer; (iii) from 30 to 75 wt.%, specifically from 35 to 65 wt.%, more specifically from 45 to 55 wt.% of tackifier resin; and (iv) from 0 to 5 wt.%, specifically from 0 to 2 wt.%, more specifically from 0 to 1 wt.% of a stabilizer such as an antioxidant.
• the present adhesive blend has improved adhesion to smooth substrates such as polyolefin films, specifically polyethylene films, and metal surfaces especially painted or coated metal substrates.
• the specific liquid/semi-liquid polymers described herein exhibit good compatibility with poly-1-butene.
• poly-1-butene polymer used herein refers a homopolymer or copolymer containing more than 50 mole% butene-1 having a melt index of from 0.05 to 5,000, specifically from 1 to 4,000, and more specifically from 20 to 2,000 dg/min., as determined by ASTM D-1238 condition E, at 190°C.
• Butene-1 homopolymers and copolymers useful with the present invention are primarily linear chain molecules with regular and spatially ordered arrangements of ethyl side groups; the groups that result when butene-1 is polymerized across the 1,2 carbon double bond along an ethylene chain backbone (see for example U.S. Pat. No. 3,362,940).
• the ethyl side groups initially align in a tetragonal crystalline phase form II transforms into a stable hexagonal spatial arrangement (form I) with subsequent development of improved physical properties.
• the polybutylene referred to herein is a butene-1 polymer containing from 90%, preferably from 95%, and more preferably from 97%, by weight of stereospecific portions. These stereospecific portions can be either isotactic or syndiotactic. As an illustrative example, isotactic poly-1 butenes having a low molecular weight, e.g. less than about 280,000 as determined by solution viscosity in "Decalin" (decahydronaphthalene) may be used.
• a butene-1 polymer usable herein is either a butene-1 homopolymer or a copolymer or a terpolymer or blends of two or more of these.
• the non-butene comonomer content is from 1 to 50 mole %, specifically from 1 to 30 mole% of either ethylene, propylene, or an alpha olefin having from 5 to 8 carbon atoms.
• Butene-1 copolymers can comprise one or more of a variety of alpha-olefins, see for example the butene-1 copolymers taught in U.S. Pat. No. 3,362,940.
• Butene-1/ethylene copolymers with ethylene comonomer in the range of 0.5-20 mole percent are expected to be useful in the inventive hot melt adhesive as the ethylene comonomer lowers the glass transition temperature (Tg) of the amorphous phase and reduces both the crystallization rate and the ultimate level of crystallinity in the polymer. It is contemplated that 5 to 15 mole %, specifically 8 to 12 mole %, comonomer content is particularly useful.
• the poly-1-butenes can be modified to increase surface activity by reaction with, for example, maleic anhydride as described in U.S. Pat. No. 4,554,304.
• Suitable poly-1-butenes can be obtained in accordance with polymerization of butene-1 with catalysts of halides of Groups IV-VI metals, e.g. titanium, vanadium, chromium, zirconium, molybdenum and tungsten, etc., and cocatalysts of metal alkyl compounds, specifically, Ziegler-Natta catalysts of titanium halides or vanadium halides with aluminum halides or aluminum alkyl (halides) compounds.
• the poly-1-butene can be obtained by a low-pressure polymerization of butene-1, e.g.
• Suitable poly-1-butenes can also be obtained using a high activity Ziegler-Natta catalyst of magnesium supported TiCl 4 , with organoaluminum or AlCl 3 cocatalyst. They can be polymerized by a gas phase, liquid phase, suspension, solution phase, or slurry polymerization process.
• Polybutylene DP0400, DP0800, DP8910PC, and DP8510 which are poly-1-butene polymers produced by Shell Chemical Company, of Houston, Texas, are suitable polymers, particularly the latter two. These polymers are copolymers of butene-1 with ethylene. The typical properties of these polymers are listed in the table below.
• modified or non-modified butene-1 homopolymers and modified or non-modified butene-1 copolymers are contemplated, it should be noted that modified or non-modified butene-1 copolymers as the butene-1 component are most preferred over butene-1 homopolymers for use within the scope of the present invention.
• the present invention has been developed to provide a butene-1 based adhesive with open time that is adjustable and controllable based on the amount and type of nucleating agent and tackifying resin blended with the butene-1 component.
• the liquid/semi-liquid polymers used herein are low viscosity polymers which are compatible with poly-1-butene used.
• the polymers used herein are viscous liquids at room temperatures and flow readily at 70°C and 80°C.
• the liquid/semi-liquid polymers become elastic after being chemically crosslinked, e.g. vulcanized.
• the liquid/semi-liquid polymers used herein are conjugated diene polymers prepared by an anionic polymerization process as described below.
• the polymers are conjugated diene block copolymers.
• the polymers are diene copolymers with either zero styrene (or vinyl aromatic hydrocarbon) content or up to 25 mole%, specifically up to 15 mole% , more specifically up to 11 mole% of styrene (or vinyl aromatic hydrocarbon).
• the polymer used contains substantially no styrene.
• the polydienes are hydrogenated or partially hydrogenated.
• the liquid/semi-liquid polymer used herein contains up to 25% unsaturation (i.e., the % of the double bonds left after the hydrogenation process), specifically up to 15% unsaturation, more specifically up to 1% unsaturation, and still more specifically up to 0.5% unsaturation.
• the molecular weights are from 2,000 to 40,000.
• the molecular weights used herein are number average molecular weights, unless specified otherwise.
• the viscosity of the liquid/semi-liquid polymer is generally from 1,000 to 10,000,000, specifically from 10,000 to 500,000, and more specifically from 20,000 to 50,000 centipoises at room temperature as measured by a Bohlin Rheometer done in parallel phase; and from 10 to 100,000, specifically from 100 to 50,000, and more specifically from 500 to 20,000 centipoises at 80°C.
• the glass transition temperatures Tg(°C) of the suitable liquid/semi-liquid polymers are generally less than about -30°C, specifically less than about -40°C, and more specifically less than about -50° C measured by Diffraction Scanning Calorimetry (DSC) second heating mid point method of 10°C per minute.
• the first type of polymer which can be used in the adhesives of the present invention is a hydrogenated styrene isoprene diblock copolymer having a molecular weight from 4000 to 30,000, preferably 6000 to 15,000, a polystyrene content of 5 to 15 percent by weight, preferably 8 to 12 percent by weight, which is at least 75 percent hydrogenated, preferably at least 85 percent hydrogenated.
• the second type of polymer which can be used in the present invention is a hydrogenated polydiene polymer which may have one diene block of either isoprene or butadiene or may be a diblock polymer wherein one block is of isoprene and the other block is of butadiene, and, optionally, wherein the polymer may have a terminal hydroxy group.
• the polymer has a molecular weight of 500 to 20,000, preferably 1000 to 10,000, and is at least 75 percent hydrogenated, preferably at least 85 percent hydrogenated.
• a preferred polydiene polymer for use in the present invention has the structural formula (HO) x -A-S z -B-(OH) y wherein A and B are polymer blocks which may be hompolymer blocks of conjugated diolefin monomers, copolymer blocks of conjugated diolefin monomers, or copolymer blocks of diolefin monomers and monoalkenyl aromatic hydrocarbon monomers. These polymers may contain up to 60 percent by weight of at least one vinyl aromatic hydrocarbon, preferably styrene. Generally, it is preferred that the A blocks should have a higher concentration of more highly substituted aliphatic double bonds than the B blocks have.
• the A blocks have a greater concentration of di-, tri-, or tetra-substituted unsaturation sites (aliphatic double bonds) per unit of block mass than do the B blocks.
• the A blocks have a number average molecular weight of 100 to 6,000, preferably 500 to 4,000, and most preferably 1,000 to 3,000
• the B blocks have a number average molecular weight of 1,000 to 15,000, preferably 2,000 to 10,000, and most preferably 3,000 to 6,000.
• S is a vinyl aromatic hydrocarbon block which may have a number average molecular weight of from 100 to 10,000.
• x and y are 0 or 1. Either x or y may be 1, but only one at a time can be 1.
• z is 0 or 1.
• the most highly preferred polymers for use herein are diblock copolymers which fall within the scope of the above formula.
• the overall number average molecular weight of such diblocks may range from 1,500 to 15,000, preferably 3,000 to 7,000.
• the diblock has the structure: I-EB-OH where I represents isoprene and EB represents hydrogenated butadiene.
• the third type of polymer is a polyisoprene homopolymer having a molecular weight of 15,000 to 40,000, preferably 20,000 to 30,000 which is at least 75 percent hydrogenated, preferably at least 85 percent hydrogenated.
• the liquid/semi-liquid hydrogenated polydiene polymers used in this invention may be prepared by contacting the monomer or monomers with an organoalkali metal compound in a suitable solvent at a temperature within the range from -150 to 300°C, preferably at a temperature within the range from 0 to 100°C.
• organoalkali metal compound in a suitable solvent at a temperature within the range from -150 to 300°C, preferably at a temperature within the range from 0 to 100°C.
• Particularly effective polymerization initiators are organolithium compounds having the general formula: RLi wherein R is an aliphatic, cycloaliphatic, alkyl-substituted cycloaliphatic, aromatic or alkyl-substituted aromatic hydrocarbon radical having from 1 to 20 carbon atoms.
• Conjugated dienes which may be polymerized anionically include those conjugated diolefins containing from 4 to 24 carbon atoms such as 1,3-butadiene, isoprene, piperylene, methylpentadiene, phenyl-butadiene, 3,4-dimethyl-1,3-hexadiene and 4,5-diethyl-1,3-octadiene.
• Isoprene and butadiene are the preferred conjugated diene monomers for use in the present invention because of their low cost and ready availability.
• Alkenyl (vinyl) aromatic hydrocarbons which may be copolymerized include vinyl aryl compounds such as styrene, various alkyl-substituted styrenes, alkoxy-substituted styrenes, vinyl napthalene and alkyl-substituted vinyl napthalenes.
• Suitable solvents include those useful in the solution polymerization of the polymer and include aliphatic, cycloaliphatic, alkyl-substituted cycloaliphatic, aromatic and alkyl-substituted aromatic hydrocarbons, ethers and mixtures thereof.
• Suitable solvents include aliphatic hydrocarbons such as butane, pentane, hexane and heptane; cycloaliphatic hydrocarbons such as cyclohexane and cycloheptane; alkyl-substituted cycloaliphatic hydrocarbons such as methylcyclohexane and methylcycloheptane; aromatic hydrocarbons such as benzene and the alkyl-substituted aromatic hydrocarbons such as toluene and xylene and ethers such as tetrahydrofuran, diethylether and di-n-butyl ether.
• aliphatic hydrocarbons such as butane, pentane, hexane and heptane
• cycloaliphatic hydrocarbons such as cyclohexane and cycloheptane
• alkyl-substituted cycloaliphatic hydrocarbons such as methylcyclohe
• Stabilizers usable within the scope of the present invention can be hindered phenols, such as Irganox 1010 (a trademark), made by Ciba Geigy Corporation, Ethanox 330 (a trademark) made by Ethyl Corporation, or phosphorus-based stabilizers such as Irgafos 168 (a trademark) made by Ciba Geigy Corp.
• Irganox 1010 is the most preferred stabilizer for use in this invention.
• the quantity of stabilizer usable within the scope of the present invention is expressed in parts by weight (pbw) based on the total amount of the components in the hot melt adhesive which are expressed in weight percent.
• Ethanox 330 is a 1,3,5-trimethyl-2,4,6-tris [3,5-di-tert.butyl-4-hydroxybenzyl] benzene.
• Irganox 1010 is usually referred to as tetrakis [methylene (3,5-di-tert.butyl-4-hydroxyhydrocinnamate)] methane. It is preferred to use about 0.3 pbw of a stabilizer, although 0.1 to 2 pbw is also usable within the scope of the invention.
• Tackifying resins usable within the scope of the present invention can be selected from the group of non-polar tackifying resins, such as Regalrez 1085 (trademark, a hydrogenated hydrocarbon resin) and Regalite Resins (trademark) such as Regalite R91 available from Hercules, Escorez 1304 (trademark, also a hydrocarbon resins) and Escorez 1102 available from Exxon Chemical Company, Wingtack 95 (trademark, a synthetic polyterpene resin), or Wingtack 85, all available from Goodyear Tire and Rubber are usable herein.
• non-polar tackifying resins such as Regalrez 1085 (trademark, a hydrogenated hydrocarbon resin) and Regalite Resins (trademark) such as Regalite R91 available from Hercules, Escorez 1304 (trademark, also a hydrocarbon resins) and Escorez 1102 available from Exxon Chemical Company, Wingtack 95 (trademark, a synthetic polyterpene resin), or Wingtack 85, all available from Good
• these resins can include: partially or completely hydrogenated C 9- or C 5 -based hydrocarbon resins, including but not limited to cyclopentadine resins, polyterpene resins aromatic C 5 resins with softening points in the range of 70°C to 125°C.
• Tackifying resins usable within the scope of this invention can include polar tackifying resins. The choice of available polar tackifying resins for use within this formulation is limited since many of the polar resins are not, at least partially, compatible with the butene-1 homopolymer and copolymers. For example, Zonester 85, (trademark) available from Arizona Chemical Company, is a polar tackifying resin usable herein.
• Tackifying resins to be used within the scope of the present invention can be 30 to 75 wt % based on the total composition, preferably 35 to 65% by weight of the total composition, and more preferably 45 to 55 % by weight of the total adhesive formulation.
• the blends of the present invention may also contain nucleating agents such as isotactic polypropylene, polyethylene, polyethylene-based waxes, fatty acid amides, amides, anthraquinones, and graphitic non-turbostratic carbon.
• nucleating agents such as isotactic polypropylene, polyethylene, polyethylene-based waxes, fatty acid amides, amides, anthraquinones, and graphitic non-turbostratic carbon.
• Other nucleating agents are also contemplated for use in this invention.
• Graphitic non-turbostratic carbon nucleating agents are disclosed in U.S. Pat. No. 4,321,334.
• Fatty acid amine nucleating agents are disclosed in U.S. Pat. No. 4,322,503.
• These fatty acid amides include specifically N,N'ethylene-bis-stearamide and stearamide.
• anthraquinones include 1,2-dihydroxy-9,10-anthraquinone; 1,4-dihydroxy-9,10 anthraquinone; 1,5-dihydroxy-9,10-anthraquinone; 12,5,8-tetrahydroxy-9,10-anthraquinone; 9,10-anthraquinone; and sodium 2-anthraquinone sulfonate.
• Amide nucleating agents are disclosed in U.S. Pat. No. 4,320,209.
• Preferred amides include 1-naphthalene acetamide; N-stearoyl-p-aminophenol; mercapto-n-2-naphthylacetamide; malonamide; nicotinamide; isonicotinamide; benzamide; phthalimide; salicylamide; anthranilamide; and 1,8-naphthalimide.
• the present adhesive compositions may also contain fillers, oils, plasticizers, amorphous poly-alpha-olefins, waxes, etc. can be utilized in combination with the above formulations.
• a preferred blend of the present invention uses about 34 to 43 wt% of a butene-1 polymer having a melt index equal to or greater than 40dg/min. (ASTM 1238 condition E) such as DP8910PC available from Shell Chemical Company; 7 to 16 wt.% of hydrogenated or partially hydrogenated conjugated polydiene (block) polymer or partially hydrogenated isoprene-butadiene block copolymer with M.W. of about 6,000 available form Shell Chemical Company; 45 to 55 wt.% of a tackifier, and 0 to 1 wt.% antioxidant, based on the total composition.
• ASTM 1238 condition E such as DP8910PC available from Shell Chemical Company
• block hydrogenated or partially hydrogenated conjugated polydiene
• isoprene-butadiene block copolymer with M.W. of about 6,000 available form Shell Chemical Company
• 45 to 55 wt.% of a tackifier, and 0 to 1 wt.% antioxidant based on the
• ethylene polymer refers to any polyethylene homopolymer or any ethylene and other olefin copolymer made by a conventional Ziegler-Natta Catalyst of Group IV-VI transition metal. Specifically the ethylene polymer is made by a vanadium metal compound, a zirconium metal compound or a titanium halide (TiCl 4 or TiCl 3 ), optionally supported by magnesium halide, with an aluminum trichloride or alkyl aluminum (halides) cocatalyst.
• Blending of the components can occur by melt compounding techniques.
• the method of combining the ingredients of the formulation is important. For example, in most cases, it is desirable to use the least amount of energy to merge the components into an effective blend. Therefore, the preferred method of blending is to first melt the poly-1-butene, and then add the liquid/semi-liquid polymer, and then add the tackifier, anti-oxidant and any other fillers, additives or modifiers.
• poly-1-butene copolymer DP8910PC (a butene-1 and ethylene copolymer having about 5.5% by weight of ethylene, available from Shell Chemical Company, Houston, TX) was first added to the mixing head of a small sigma blade mixer and mixed for 45 minutes until smooth. A low viscosity, Liquid or semi-liquid elastomer was then added and mixed for 15 minutes. Thereafter, ESCOREZ 1102, a C 5 type solid tackifying resin (available from Exxon Chemical Company) and IRGANOX 1010, a phenolic antioxidant antioxidant (available from Ciba Geigy) were added and mixed for an additional 20 minutes.
• ESCOREZ 1102 a C 5 type solid tackifying resin (available from Exxon Chemical Company) and IRGANOX 1010, a phenolic antioxidant antioxidant (available from Ciba Geigy) were added and mixed for an additional 20 minutes.
• the mixing temperature was approximately 180°C, and the mixing speed was 60 rpm.
• a 10 cfm nitrogen purge was used in the mixing head.
• the following low viscosity, Liquid or semi-liquid elastomeric polymer were used in the formulations:
• the adhesives were spray coated at various temperatures using a PAM 600 Spraymatic melt coater gun onto a sheet of 35.6 ⁇ m polyethylene diaper film supplied by 3M. Following coating, the film was folded together, laminated, and rolled down with a 2 kg rubber coated roller. The adhesive laminates were aged at room temperature for 5 days. Strips of about 2.5 cm wide were cut from the laminated film, and the peel adhesion was observed by pulling the strips apart by hand. Table 2 also shows a qualitative analysis of the peel adhesion failure mechanism observed.
• the mixing temperatures were approximately 180 to 193 °C.
• a 10 cfm nitrogen purge was used in the mixing head at all times to minimize degradation.
• the polybutylene was first added to the mixing head and mixed for 45 minutes until smooth. Subsequently, liquid polymer was added and mixed for 15 minutes. Thereafter, solid tackifying resin and antioxidant were added and mixed an additional 20 minutes.
• the formulations are shown in Table 3.
• the adhesives were spray coated on a melt blown adhesive coating line.
• the adhesives were melted on a DM-90 Gridmelter at 166 to 180 °C.
• Process air was heated to 193°C at 380 kPa using a DH-15 compressor/heater.
• S.S.T. die tips (orifice diameter - 0.5 mm) melt sprayed a 13.3 cm wide intermingled melt pattern on a 15.2 cm wide polyethylene film (50.8 ⁇ m) moving at 91.4 m/minute.
• the forming distance was 5.1 cm.
• the coated film was laminated with a second 15.2 cm wide film with a nip pressure of 345 kPa.
• the melt pump speed was controlled to lay down adhesive add on weights of 10, 5, 2.5, 1.25, and 0.625 grams adhesive per square meter.
• Table 4 shows the average and initial peel force for all 19 samples produced and provides the processing information regarding the 19 samples.
• control samples based on polybutylene and tackifier had very low peel values at several coating weights.
• the addition of the liquid block polymers improves the peel values of the adhesives.
• Samples B7 and C8 were coated at 10 grams adhesive/square meter. The large amount of adhesive appeared to have melted and fused the substrates together, producing a polytear.
• Table 4 shows the effect of coating weight on the peel values obtained. Note that although the peel value decreases as a function of coating weight, very respectful peel values can be obtained at very low coating weights using Polymer-L as a modifier of polybutylene.
• the adhesive blends of the present invention have improved adhesion to smooth surface polyethylene films as compared to polyisobutylene-containing adhesive blends.

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